Interatividade entre bioinsumos e genótipos de milho: adaptação ao estresse hídrico

Abstract

Agricultural intensification is causing significant pressure on land use, resulting in soil salinization, desertification, eutrophication of water bodies and the loss of soil microbial diversity. These processes affect the sustainability of agricultural production systems, and require innovations to increase productivity without harming natural resources. This search for sustainable alternatives is particularly necessary for large economically and socially important crops, such as maize. Among the various possible alternatives to meet this need, the use of microorganisms in the agricultural sector is on the rise. Our first article investigated the effectiveness of different physiological conditioning methods, with and without bioinputs, in promoting early growth of three hybrid maize cultivars recommended for Sergipe (AS1850PRO4, P3707VY and NS45 VIP3). Inocula based on Bacillus amyloliquefaciens, B. subtilis and B. pumilus were used as bioinputs, during inoculation periods of 0, 2, 4 and 6h. The variations between treatments and genotypes were significant. The studied variables were germination, seedling area, number of root branches, root-hypocotyl ratio, hypocotyl size, root size, total seedling size, and general (GCA) and specific combining ability (SCA). None of the treatments with genotype AS1850PRO4 outperformed the control group in hypocotyl size, indicating that the bioinputs were not beneficial for this parameter. However, in the B. pumilus treatment, primary root development was better at all times tested, suggesting a specific potential to improve the root system. Although bioinputs may not significantly influence overall seedling growth, they can improve specific aspects of early plant development, e.g., of the root system. For GCA for primary root development, genotype NS45 VIP3 achieved the best results, indicating a strong positive genetic impact of this genotype on the trait. In the second article, four genotypes (three hybrid cultivars, P3707VYH, NS45 VIP3, AS1850 PRO4, and the landrace variety “Pé-de-boi”) were evaluated. The interactions of these genotypes with the bioinputs containing B. aryabhattai, B. pumilus, B. amyloliquefaciens, B. subtilis and the control treatment were evaluated. The B. amyloliquefaciens treatment was effective in promoting seedling growth of genotype AS1850PRO4. The treatment resulted in better performance under stress, with an increase of 87% in seedling shoot length. For AS1850PRO4, gains of 32.62% in total seedling size were reported, although this effect was not observed in any of the other genotypes. For genotype NS45VIP3, performance under stress was poorer, and the main root size in the B. aryabhattai treatment was 23% shorter than in the stress treatment. Significant improvements in seedling development were only observed in the B. amyloliquefaciens treatment, compared to the stress treatments. Significant and positive interactions with the bioinputs were only observed for genotype AS1850PRO4.